Complex temporal patterns of firing rate in response to odor stimuli have been observed in the olfactory bulb output cells (Mitral and Tufted cells) of many species and have been proposed as candidate codes for both odor quality and intensity. These temporal patterns could be generated by the neural circuits of the olfactory bulb or they could be imposed on the bulb by a temporally patterned afferent input. Combined odor and electrical stimulation will be used to distinguish between 1) changes in output due to changes in afferent input and 2) changes due to inhibition in the bulb. The uptake of labelled 2 -deoxyglucose (2DG) in restricted areas of the olfactory bulb suggests that there is also a spatial pattern of activity in the bulb during exposure to odors. These experiment also suggest that the restricted area of activation in the bulb enlarges as concentration is increased. Preliminary results and computer simulation suggest that the temporally patterned responses may be generated as a result of the spatially patterned input. The laterally connected neural network of the bulb should generate waves of excitation and surround inhibition when subjected to a spatially restricted afferent input which expands and contracts with the rise and fall of concentration during odor stimulation. The spatial distribution of activity in the areas of the bulb showing odor elicited uptake of 2DG will be reconstructed by plotting the responses of cells recorded on multiple electrode tracks though that area. The temporal patterns of response of these same cells to a variety of odor stimuli will be recorded Any systematic relationship between a cell's spatial location, with respect to the area of input, and its temporal pattern of response will be analysed with regard to the anatomically described lateral interactions in the bulb. These experiments should further our understanding of the function of a cortically organized neural network receiving natural patterns of input. The results can contribute to an understanding of 1) the function of other cortically organized structures including the human cortex and 2) the neural mechanisms involved in the discrimination of odors in all mammalian brains.